Navigator 2.0, Internet Explorer 3.0
function.arguments[i] function.arguments.length
The arguments property of a Function object is an array of the arguments that are passed to a function. arguments.length specifies the number of elements in the array. JavaScript allows any number and any type of arguments to be passed to a function, and the arguments[] array allows you to write functions that can gracefully accept a variable number of arguments.
If the function was defined with n argument names, then the first n elements in the arguments[] array may also be referenced through the defined argument names.
See Function for more details on the use of this property.